Try the Ampeg PF500 head, and most importantly, 2 of the PF115's. A single 15 is nice, but 2 of them is where you get loud volume. (suggested this because you stated Ampeg). Otoh, any good 300+ watt amp paired with enough spkr to get the volume you require. As a minimum, 4x10, 2x12, 2x15 are good "mid-sized" cabs. Real loud volume = 8x10, 4x12, etc. You might also try keeping your GK head, (great amp), sell the 210 and get a bigger, better cab. Add a Sansamp pedal in front to get Ampeggish tones.